This invention relates in general to liquid fuel space heaters, and more particularly to compact, forced air space heaters for small closed areas such as vehicle cabs.
An increased realization of the need to conserve energy, and, in particular petroleum distillate fossil fuels or equivalents, has led to attempts to develop energy-efficient space heaters which provide, in a safe and reliable manner, maximum heat output per unit of liquid fuel.
For example, U.S. Pat. No. 3,964,859 to Nishi et al discloses a compact liquid fuel space heater utilizing a flame sensor-regulated metering pump, feeding an impeller-type, heated chamber fuel vaporizer. The Nishi et al heater incorporates numerous temperature sensors and temperature-regulated control elements in an attempt to obtain and maintain optimum fuel combustion. U.S. Pat. No. 3,086,579 to Brown and its U.S. Pat. No. Re. 25,970 disclose a ceramic block heating element, liquid fuel space heater having a non-temperature regulated fuel applying device for establishing a generally constant operating temperature of the heater.
While such devices may increase fuel consumption efficiency and provide a small capacity heater suitable for fulfilling vehicle cab heating requirements, their complexity necessarily leads to reliability problems. Such reliability problems become especially significant where heaters of the type described are installed in the cabs of vehicles that travel great distances from maintenance facilities. The possibility of such a vehicle being stranded in, for example, a blizzard or the like requires that the cab space heater be extremely reliable and safe to operate.